There is a new pull request by Ophidiophobia against master on the void-packages repository

https://github.com/Ophidiophobia/void-packages megatools_10.3
https://github.com/void-linux/void-packages/pull/21201

megatools: update to 1.10.3 fixes #20820
Tested it on a few old links and they work with that update.

Quoting upstream:
> megatools 1.10.3 - 2020-04-15
> =============================
> 
> This is a bugfix release.
> 
> Fixes:
> - Add support for new format of mega.nz links (by Alberto Garcia)

A patch file from https://github.com/void-linux/void-packages/pull/21201.patch is attached